Knitting machine



1942- A. E. STEWART 2,271,902

KNITTING MACHINE Filed Nov. 6, 1959 2 Sheets-Sheet 1 ATTORNEY.

Feb. 3, 1942. A. E. STEWART 2,271,902

KNITTING MACHINE Filed Nov. 6, 1959 2 Sheets-Sheet 2 INVENTOR. [B IATTORNEY;

Patented Feb. 3, 1942 KNITTING MACHINE.

Albert E. Stewart, Franklin, N. H., assignor to Acme Knitting Machine &Needle Company,

Franklin, N. H., Hampshire corporation of New Application November 6,1939, Serial No. 303,089

9 Claims. (01. 66-158) This invention relates to knitting machines andis more especially concerned with mechanisms designed to stop a machineof this type automatically in the event that the thread with which theknitting operation is being performed breaks or runs out.

Such mechanisms are in common use, and they are very valuable inpreventing the production of imperfect work under circumstances such asthose just described. Also in certain types of machines they prevent thebreakage of needles or latches which would occur if one of two threadsrunning to the needles breaks and the nature of the knittinginstrumentalities is such that the machine continues to operate with theremaining thread which accumulates or piles up- On the needles.

The invention aims to improve stop mechanisms of this general characterwith a view to simplifying their construction, making them morereliable, and reducing the expense of manufacturing and installing them.

The nature of the invention will be readily understood from thefollowing description when read in connection with the accompanyingdrawings, and the novel features will be particularly pointed out in theappended claims.

In the drawings,

Figure 1 is a side elevation of parts of a circular knitting machineequipped with an automatic stop mechanism constructed in accordance withthis invention;

Fig. 2 is a front view of the machine and stop mechanism shown in Fig.1; and

Fig. 3 is an elevation, on a somewhat larger scale, of those parts atthe upper end of the mechanism.

The machine shown in the drawings is designed more especially for theautomatic production of circular knit stockings, The illustration of it,in general, has been limited to those features with which the presentinvention is more especially concerned. It includes a needle cylinder 2mounted on a base 3 of a common form, and a thread ring 4 cooperatingtherewith. A single thread T is shown running from a suitable supply,bobbin, or spool (not shown) through a thread tension device 5 of acommon form, and thence to the knitting instrumentalities.

It is a common practice in machines of this type to include a clutch ora fast and loose pulley in the driving connections so that the machinemay be stopped by throwing the clutch out or shifting a driving beltfrom the fast-to the loose pulley. In either case a knock-off mechanismis usually provided to control the clutch or the belt. A commonarrangement is that shown in Fig. 2 in which a rock shaft 6 is providedto operate the clutch or the belt shipper, and the 7 rock shaft, inturn, is operated by a hand lever l. A link 8 is slidably connected tothe lever and is provided at its end remote therefrom with a notch [0.Thus the link forms a latch, and a coiled spring l2 connected with it,as shown in So far as the general organization above described isconcerned, it is of a common form and it may be of any other suitable orconvenient nature.

This invention is directed to the provision of a controlling means forthe knock-off mechanism which will release the latch when the threadbreaks or fails for any reason, as by running out. In priorconstructions the operation of such controlling means is dependent uponthe use of springs, and it is one of the objects of this invention toeliminate springs, with their inherent defects and objectionablecharacteristics, from the action of those parts which feel for thepresence of the thread and preferably from the entire controllingmechanism.

The controlling mechanismillustrated in the drawings comprises a threadguiding finger or feeler l5 which may conveniently consist of a wirebent into suitable form and having an eye or hook at its forward end toengage and guide the thread T. This feeler is adjustably clamped in aholder It by means of a set screw H, the holder being mounted to rock orpivot freely on a rock shaft [8. The rearward end portion of the wire I5is bent, as shown in Fig.v 1, to provide a portion above, and parallelwith, the main body breaks or runs out, the feeler is instantlyxre-ileased, the weight 20 swings in a counter-clockwise direction around theaxis of the rock shaft l8, together with the support [6, and afterswinging for a considerable distance and thus acquiring momentum, thefeeler wire strikes a pin 22 fixed in an arm 23 which is pinned to therock shaft H3. The outer end of this rock shaft has a plate 24 securedthereto, and a pin 25 projecting laterally from said plate normallyoverlies the end of a weighted lever 26, as shown in Fig. 1, and thusrestrains it, or acts as a latch for it. At this time the pin is in thesame vertical plane with the axis of the rock shaft l8 to which the pinsupporting plate 24 is secured. The shaft !8 rocks freely in itsbearings 2'!--21 and consequently, when the feeler I strikes the pin 22,as above described, it rocks the shaft It in a counterclockwisedirection, Fig. 1, and thus moves the pin or latch 25 off the end of thelever 26. This action is accomplished with certainty because of therelatively heavy impact delivered by the feeler, and the parts movablewith it, when it strikes the pin 22.

Immediately upon the release of the weighted lever 26, it swings aboutits fulcrum 28 and the pin or screw 33 projecting laterally from it andrunning in the slot 3| of the link 32, strikes the lower end of thisslot with a very substantial degree of momentum. This blow or impact istransmitted to the upwardly extending arm A of the bell crank lever l3and trips the latch 8 of the knock-off mechanism, allowing it to shutdown the machine.

It will be seen from the foregoing that the controlling mechanism hereshown includes a primary latch H)l3 which normally restreins theknock-off mechanism but is arranged to be released by the action of thegravity impact element 2%. This element, in turn, is normally restrainedby a secondary latch 25 adapted to be released upon the breaking orrunning out of the thread by the action of a second gravity impactelement consisting of the weighted feeler assembly. Such a mechanism isextremely reliable in operation. At the same time it is simple in itsconstruction, the parts can be manufactured and assembled economically,and it is of such a nature that the matter of installation is relativelysimple. Also, because of the mounting of the weight 20 above the axis ofthe pivot IS on which the feeler swings and the adjustability of thisweight, the force exerted by it to tension the thread can be adjustedvery precisely, while at the same time the impact which it will deliverwhen the thread breaks is ample to operate the latch 25.

In the event that the work being produced requires the substitution ofone or more threads for that shown at T, as for example, in knitting theheel and toe of a stocking, the thread T will be cut off by the usualthread changing mechanism and its end may be left free, or comparativelyso. Thus, if such a thread change were to occur, the feeler wouldimmediately be released and would initiate the operation of theknock-off mechanism, thus shutting down the machine. In order to preventsuch an occurrence, the mechanism above described preferably is placedunder the control of the pattern mechanism of the machine. As shown inFig, 1, this object is accomplished by mounting a cam disk 34 on the camshaft 35 of the pattern mechanism and providing this disk with one ormore cam lugs such as B or C where they will operate a lever 36. A link31 connects this lever with another lever 38, fulcrumed on the machineframe at 40, Figs. 2 and 3. So long as the lever 36 is not resting on acam lug on the disk 34, its weight operates through the connections justdescribed to hold the right-hand end, Figs. 2 and 3, of the lever 38against the lower face of the feeler holder l-6 where it maintains thisfeeler, the rock shaft 18 and the latch pin 25 locked against movementunder the influence of those forces which otherwise would actuate them.When so looked a lug 39, Fig, 3, projecting downwardly from the holderIt bears against the rearward side of the right-hand end of the lever 38and prevents any rotation of the holder out of its operating position.At this time the thread T is not being used but the knittinginstrumentalities are working with another thread or threads. When,however, the pattern mechanism changes threads again and brings thethread T into feeding position, it also moves a lug under the end of thelever 36 and releases the brake lever 38. In a typical stocking the lugsB and C would control the lever during the knitting of foot and legportions, respectively, of the stocking, and the feeler mechanism wouldbe held in an inactive or inoperative condition during the knitting ofthe remaining portions of the stocking.

After the knock-off mechanism has been actuated and has shut down themachine, and the starting lever 1 is again swung to the left, Fig. 2, tostart up the machine, the link -8 is automatically latched by the triplever 3 due to the fact that it tends to swing in a counter-clockwisedirection, Fig. 1, by gravity. The feeler mechanism is returned to itsnormal position, as shown in Fig. l, and the lever 26 is re-latched bythe pin 25, also as there shown. This completes the re-setting of thecontrolling mechanism. A second pin 4|, Fig. 1, carried by the plate 24,engages a frame plate 42 when the latch pin 25 is in its operativeposition and holds the rock shaft and the arm 23, pinned thereto, inposition for subsequent operation by the feeler.

While I have herein shown and described a preferred embodiment of myinvention, it will be evident that the invention may be embodied inother forms without departing from the spirit or scope thereof,

Having thus described my invention, what I desire to claim as new is:

1. In an automatic stop mechanism for knitting machines, the combinationwith a knock-off mechanism, of controlling means therefor comprisingprimary and secondary latches, a gravity impact element normallyrestrained by the thread running to the knitting instrumentalities andadapted when released by the breaking of the thread to release thesecondary latch, a second gravity impact element normally restrained bysaid secondary latch but arranged to be released by said first impactelement for releasing the primary latch and means continuouslyconnecting said second gravity impact element with said primary latchand serving to transmit motion from one of these parts to the other.

2. In an automatic stop mechanism for knitting machines, the combinationwith a knock-off mechanism, of controlling means therefor including alatch restraining said mechanism, a weighted member connected with saidlatch to release it, means supporting said member for operative swingingmovement, a second latch normally restraining said member, and a pivotedand weighted feeler normally controlled by the thread running to theknitting instrumentalities and operable upon the breakage of said threadto release said second latch through the momentum developed in itsmovement out of its operative position and means connecting saidweighted member with the first mentioned latch for tran mitting movementfrom each of said members to the other.

3. In an automatic stop mechanism for knitting machines, the combinationwith a knock-01f mechanism, of controlling means therefor including alatch restraining said mechanism, a weighted member connected with saidlatch to release it, a second latch normally restraining said member, afeeler having a horizontally extending arm engaging the thread runningto said knitting instrumentalities, a horizontal pivot supporting saidfeeler, a weight movable with said feeler and mounted directly above thepivotal support for the latter in an approximately balanced position butso biased as to apply tension to said thread, whereby when the threadbreaks or runs out the feeler will be released and said weight willswing downwardly around said pivot, and means arranged to be struck by apart movable with said weight during such swinging movement to releasesaid second latch due to the impact of said part.

4. In an automatic stop mechanism for knitting machines, the combinationwith a knock-off mechanism, of controlling means therefor including alatch, and means for releasing said latch comprising a feeler supportedin a generally horizontal position and engaging the threadrunning to theknitting instrumentalities, a weight connected with said feeler to bemoved thereby in response to variations in tension of said thread, meanssupporting said weight for swinging movement about an axis directlyunder it, said weight being so positioned with reference to said axisthat it is approximately balanced but is so biased as to operate throughits connections with said feeler to apply a moderate degree of tensionto the thread, whereby when the thread breaks or runs out the feelerwill be released and said weight will swing downwardly around said pivotinto a latch releasing position, said weight and the feeler assemblyhaving sufficient mass to deliver an impact serving to release thelatch.

5. In an automatic stop mechanism for knitting machines, the combinationof a thread guiding feeler, means supporting said feeler in a generallyhorizontal position, said means including a holder mounted to swingabout a horizontal axis disposed transversely to the feeler, a weightmounted for movement around said axis and connected with said feeler tobe moved thereby in response to variations in the tension of saidthread, said weight being mounted directly over said axis in anapproximately balanced position, and mechanism for stopping said machineincluding an operating element 25 and a latch normally restraining saidelement but mounted for releasing movement around said axis and arrangedto be released by the impact of the feeler assembly, including saidweight, delivered upon the breaking or running out of the thread.

6. In an automatic stop mechanism for knitting machines, the combinationwith a knock-oil mechanism, of controlling means therefor including alatch, a pivoted and weighted feeler normally restrained by the threadrunning to the knitting instrumentalities, connections arranged to beoperated by the release of said feeler for tripping said latch, andmeans controlled by the pattern mechanism of the machine for lockingsaid feeler in its operative position during certain of the knittingoperations and automatically releasing it to the control of said threadat other times.

7. In an automatic stop mechanism for kniting machines, the combinationwith a knock-oil mechanism, of controlling means therefor including alatch, means for releasing said latch comprising a feeler engaging thethread running to the knitting instrumentalities, a pivoted and weightedsupport for said feeler normally governed as to position by the actionof said thread on said feeler, said feeler'assembly being so biased asto swing by gravity into a latch releasing position upon the breakage ofsaid thread and having sufficient mass to deliver an impact serving torelease the latch, and means controlled by the pattern mechanism of themachine for locking said controlling means in its operative position butin an inoperative condition during the knitting of certain portions ofthe work and releasing it automatically while other portions are beingknit.

8. In an automatic stop mechanism for knitting machines, the combinationwith a knock-off mechanism, of controlling means therefor comprisingprimary and secondary latches, a gravity impact element normallyrestrained by the thread running to the knitting instrumentalities andadapted when released by the breaking of the thread to release thesecondary latch, a second gravity impact element normally restrained bybut arranged to be released by said first impact element for releasingthe primary latch, and means controlled by the pattern mechanism of themachine for holding said secondary latch releasing means in itsoperative position but in an inoperative condition during the knittingof certain portions of the work and restoring it again to an operativecondition while other portions are being knit.

9. In an automatic stop mechanism for knitting machines, the combinationof a thread guiding feeler, means supporting said feeler in a generallyhorizontal position, said means including a holder mounted to swingabout a horizontal axis disposed transversely to the feeler, a weightmounted for movement around said axis and connected with said feeler tobe moved thereby in response to variations in the tension of saidthread, said weight being mounted directly over ing a slotted link.

ALBERT E. STEWART.

